**Question:**

In the given circuit the internal resistance of the $18 \mathrm{~V}$ cell is negligible. If $R_{1}=400 \Omega, R_{3}=100 \Omega$ and $R_{4}=500 \Omega$ and the reading of an ideal voltmeter across $\mathrm{R}_{4}$ is $5 \mathrm{~V}$, then the value of $R_{2}$ will be:

Correct Option: 1

**Solution:**

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